Corrosion protection mechanism of 2-mercaptobenzothiazole and its potential synergistic effect with cerium ions for treatment of AA 2024-T3

Abstract

The corrosion protection mechanism of 2-mercaptobenzothiazole (2-MBT) and its potential synergistic effect with cerium chloride (CeCl3) for sustainability of the aerospace alloy AA 2024-T3 was investigated. The corrosion inhibitors 2-MBT and CeCl3 and their potential synergistic properties were assessed with image-assisted electrochemical noise, the split-cell technique, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM) observations. It is suggested that 2-MBT inhibits the dealloying of S-phase particles and prevents the formation of Cu-rich particles on the surface of AA 2024-T3. 2-MBT protects the second phase particles from corrosion and offers sustainability in 3.5% NaCl solution by formation of a protective layer on the surface of AA 2024-T3. Additionally, 2-MBT is adsorbed on the surface of AA 2024-T3 during anodic dissolution of aluminium. A synergistic effect between 2-MBT and the Ce3+ based corrosion inhibitor was not found. It is suggested that 2-MBT protects the intermetallic particles from corrosion from the early immersion time and blocks the precipitation of cerium hydroxides over the second phase particles. 2-MBT revealed better corrosion protection properties compared with CeCl3 and 2-MBT + CeCl3 in the tested time scale.